Electrical plug connections enjoy a wide variety of applications. It must initially be distinguished between A electrical plug connections for connecting individual devices via a direct connection or via a cable-attached connection. In the first case, direct connection, the devices to be brought into contact are done so directly via suitable plug connections; they are therefore in direct contact with one another and do not require a cable. Such direct connections find application for example in so-called docking stations, with which a portable computer can be integrated into a stationary computer system. In the second case, cable-attached, the devices to be in contact have suitable connectors such as plugs or sockets and are connected to each other via one or more cables.
Plug connections must be further classified as those with a security mechanism to protect against mechanical separation of the connection and those without such a mechanism. In the case of plug connections without a security mechanism, the mechanical grip of the connectors is effected primarily by friction between the connectors, but it is not protected from intentional or unintentional separation of the connection. In the case of connections with a mechanism safeguarding against mechanical separation of the connection, there is an intentional mechanical locking between the connecting elements themselves, in addition to a mechanical engagement of the connectors. This can be effected for example by threading, clamping, or latching.
Finally, in the case of plug connections with a mechanism to prevent mechanical slippage, distinction must be made between those with a fixed connection and those with a pull-apart separation function, for example when a tensile load exceeding a certain threshold is exerted. The former are effected primarily with screws, while the latter preferably have spring-loaded latching contacts that--with no tensile load--engage one another and, when a certain tensile load is applied, disengage and release the connection.
Electrical plug connections with a locking function are used almost exclusively for cable-attached connections and find only limited application in direct connections such as in a docking station. In particular, mechanical locking mechanisms with a pull-apart function under tensile load are not suited to use in direct connections, since it is usually undesirable to pull apart the devices connected by the plug connection in order to effect mechanical unlocking. Therefore, for a direct connection or cable-attached connection with integrated separation function under tensile load, different plug connections must be provided to prevent interference of the locking mechanisms.
FIG. 1 shows a prior art electrical plug connection. A plug 10 (male) is to be connected to a corresponding, complementarily shaped socket 20 (female). The plug 10 has contact elements 30 in a housing 40, a cable 50, and latching elements 60A and 60B. Socket 20, which for example can be built into a housing, has contact elements 70 complementary to the contact elements 30, a contact body 80, and latching elements 90A and 90B. When plug 10 and socket 20 are interconnected, latching elements 60B and 90B as well as 60A and 90A engage one another. This produces an integrated pull-apart function under tensile load exerted for example on cable 50, whereby the maximum tensile load, which leads to separation, depends on the geometric design of the latching elements 60A, 60B, and 90A, 90B, and in particular on the shape of any undercut 95A, 95B, as well as on the material used in this case.
When using socket 20 for a direct connection, the latching elements 90A and 90B are typically omitted.